Microfilm flow type apparatus

ABSTRACT

An apparatus for scanning a succession of sheets which are transported through a scanning station; the scanning apparatus is useful, for example, in the reproduction of the material on such sheets on microfilm. A first driven transport means conducts the sheets to the scanning station; a second driven transport means conducts them away from such station. The two transport means are driven by a common motor which is under the control of a novel circuit means which stops the motor if a sheet, having been grasped and conveyed by the first transport means, fails to reach the second transport means within a predetermined time interval thereafter. The circuit also provides for the control of the film transport of an associated camera, and for the counting of sheets passing through the apparatus.

United States Patent Hofmann et al.

[ Sept. 5, 1972 p [22] Filed:

[541- MICROFILM FLOW TYPE APPARATUS [72] Inventors: Wiliried Hofmann,Munich; Josef Pfeifer, Unterhaching, both of Germany [73] Assignee:Agfa-Gevaert 'AG, Leverkusen,

Leverkusen, Germany April 15, 1970 [21] Appl. No.: 28,611

[51] Int. Cl ..G03b 27/32 [58] Field of Search ..355/l4, 50, 64

[56] References Cited UNITED STATES PATENTS 2,461,185 2/1949 Schubert..355/64 Primary Examiner-John M. Horan Attorney-Arthur O. Klein [57]ABSTRACT An apparatus for scanning a succession of sheets which aretransported through a scanning station; the scanning apparatus isuseful, for example, in the reproduction of the material on such sheetson microfilm. A first driven transport means conducts the sheets to thescanning station; a second driven transport means conducts them awayfrom such station. The two transport means are driven by a common motorwhich is under the control of a novel circuit means which stops themotor if a sheet, having been grasped and conveyed by the firsttransport means, fails to reach the second transport means within apredetermined time interval thereafter. The circuit also provides forthe control of the film transport of an associated camera, and for thecounting of sheets passing through the apparatus.

6 Claims, 3 Drawing Figures PATENTEDSEP 5 m2 SHEET 1 BF 3 IN VEN TORWILFRIED HOFMANN BY: JOSEF PFEIFER 0. QM"

AHor n ey PA'TENTED SEP 5 m2 3.689.151

' sumenrs Fig.

INVENTORS WILFRIED HOFMANN BY JOSEF PFEIFER PATENTED SE? 5 I973 SHEET 3BF 3 IN V EN T0125:

WILFRIED HOFMANN JOSEF PFEIFER Mar-nay MICROFILM FLOW TYPE APPARATUS Theinvention relates to a microfilm flow type apparatus having apicture-scanning window in the scanning plane of the apparatus andtransport means for the carriers of the subject matter which is to bescannedThe invention will be disclosed principally in connection withits use with a flow type camera, although its use is obviously notrestrictedthereto.

Microfilm cameras operating under the continuous flow principle usuallyinclude means which grasp the subject matter or sheet which is to bereproduced after it has been inserted into the machine and transportthis sheet into a plane where it is being photographed. After the sheethas passed through the photographic plane, it is seized by a secondtransport system and is moved out of the microfilm camera. In thephotographic plane itself the sheet to be photographed is normallyguided by means of a pair of transparent plates. Damaged sheets orstaples, which have inadvertantly not been removed from the sheets,frequently jam the guide means of the camera. All the material whichfollows in the apparatus, for example the sheets which are fed by anautomatic feeder into the machine, are then also jammed and may beconsiderably damaged by mashing and may even be partially destroyed.

The apparatus in accordance with the illustrative embodiment of theinvention has switching means mounted along the path followed by thesheet traversing the picture window being scanned by the camera. A firstswitch activates a delay member of a relay, and a second switchinterrupts a pulse which is started by the first switch. The delayperiod of the delay member corresponds at least to the period it takesfor the travel of the sheet between the two switches.

In this arrangement according to the invention the relay is energized assoon as the time of travel of the sheet between the two switches exceedsthe exact predetermined interval which it should normally take, plus apredetermined tolerance. Any type of disturbances occurring in thetransport means of the camera, no matter what the source of thedisturbance is, is detected with great accuracy.

In the illustrative embodiment, the relay when energized, stops themotor driving the sheet traverse or feeding means. It is, of course,also possible to have the relay actuate an optical or acoustical signalwhich would indicate to persons servicing the microfilm camera that theyshould undertake certain measures. The avoidance of damage to the sheetsto be photographed can be even more effectively accomplished withgreater security when the relay, as indicated above, is a magnetic relaywhich de-energizes the sheet transport means by means of a circuitgoverned by the magnetic relay. In the illustrative embodiment, thecircuit for the magnetic relay has a first switching means which isclosed when the sheet to be photographed has reached a predeterminedpoint along its pass through the microfilm camera. The circuit isfurthermore provided with a second switch and a time-delayed electronicswitch, said second switch being opened when the sheet reaches a secondpoint along its path through the microfilm camera. The time-delayelectronic switch has a time-delay RC circuit connected in parallel tothe magnetic relay, the R-C circuit activating the electronic switchafter both the first and second switch have remained closed for apredetermined time.

According to a further feature of the invention, the electronic switchincludes in a known manner a controlled rectifier having a controlelectrode, the control electrode of the rectifier being connected to thebase of a unijunction transistor, the emitter of which is connected tothe RC circuit and the second base of which is connected to the secondswitch. The use of a controlled rectifier, such as a thyristor, makes itpossible to make the circuit particularly compact and efficient. The useof an RC circuit as well as a unijunction transistor controlled by thesecond switch, makes it possible to discharge the condenser quicklybetween the working cycles without additional discharge switches or thelike.

A particularly simple arrangement for a microfilm flow type camera whichis free from malfunctioning results when the magnetic relay is disposedin the circuit of the main drive motor for the sheet transport means andwhen the film transport driving means of the camera are provided with amagnetic clutch which is controlled by means of the first switch.

Since the second switch fails to open only when a sheet fails to pass itin the required time interval, it is possible, according to a furtheradvantageous feature of the invention, to provide this second switchwith a counter to count the number of photographs taken withoutmalfunctioning of the device. I

The accompanying drawings show one non-limiting embodiment of theinvention by way of example.

In the drawings:

FIG. 1 is a somewhat schematic view, partially in vertical longitudinalsection and partially in side elevation, of an apparatus which scans asheet on both sides as the sheet is carried therethrough, said apparatusbeing adapted for use with a microfilm flow type camera;

FIG. 2 is a circuit diagram of the apparatus in ac- I cordance with theinvention; and

FIG. 3 is a fragmentary view in perspective of a camera incorporatingthe scanning apparatus of FIGS. 1 and 2.

In FIG. 1 there is illustrated a housing for the scanning mechanism ofthe invention, said housing also serving to house camera apparatus, notparticularly shown. Housing 1 has an input opening la through which asheet 13 to be scanned and reproduced may be inserted in the directionof the arrow A. After the sheet has been introduced, it is seized by afirst endless belt 7 which is entrained around guide rollers 2, 3, 5, 6and 4, and is driven in the direction shown. The sheet is moved on theupper horizontal run of belt 7 beneath a horizontal guide plate 10, thesheet being diverted from a horizontal path to a vertical one at roll 4where it passes between the belt and the roll. After leaving the zone ofrollers 6, 9 the sheet 13 travels upwardly between two glass plates 11and 12 which form the picture window of the camera. One or more of theguide rollers 2 to 6 inclusive, or the transport rollers 8 and 9 whichpress against the belt 7 and guide rollers 2 and 6, respectively, areconnected in a known manner to a motor 33, which in this embodimentdrives both the sheet transport mechanism and the associated flow typecamera. The sheet 13 is illuminated on both sides in the picture windows11, 12 by means of a row of lamps 14, 15. There are provided usualmirror arrangements 16 and 17, which are conventional in microfilm flowtype cameras for the simultaneous photographing of both sides of a sheetin a microfilm camera. As above noted, the camera has not beenillustrated in detail in the drawings.

After the sheet 13 has traversed the picture windows 1 1, 12, it istaken up by parallel endless transport bands 18 which are mounted aroundthe rollers 19, 20 and 21. Confronting and pressing against the bands'18 at rollers 19, and 20, 21, respectively there are transport rollers22 and 23, which with a guide member 24 aid in the upward transportingof the sheet. By means of this second sheet transport arrangement, thesheet 13 is moved in the direction of the arrow B out of the camera.

A first sheet detecting means is mounted in advance of the scanningstation defined by the picture windows 11, 12 through which the sheet 13passes. Such first sheet detecting means comprises a feeler 26 pivotallymounted on a shaft 25, the feeler being in the form of a first-classlever having a first arm 26a which extends into the plane of the pathtaken by the sheet as it travels to the scanning station. The second arm26b of the feeler 26 is connected with an actuating lever 27 of a firstmicroswitch 28. Microswitch 28 is normally open, being closed only whena sheet 13 engages feeler 26a.

A second sheet detecting means is mounted downstream of the scanningstation defined by the picture windows ll, 12. Such second sheetdetecting means comprises a feeler 30 pivotally mounted on a shaft 29,the feeler being in the form of a first-class lever having a first arm300 which extends into the plane of the path taken by the sheet as ittravels away from the scanning station. The second arm 30b of the feeler30 is connected with an actuating lever 31 of a second microswitch 32.Microswitch 32 is normally closed, being opened only when a sheet 13engages feeler 301;.

As shown in FIG. 2, microswitches 28 and 32 are incorporated in acircuit for energizing the coil of a magnetic relay 34 which controlsthe on and off switching of the motor 33 for driving the sheet scanningmechanism, above described, and the film transport of a microfilm flowtype camera with which the scanning mechanism is associated.

The magnetic relay 34 is energized by a DC power source which isconnected to the relay by means of conductor wires 35 and 36,microswitches 28 and 32 being interposed in series in wire 35. The drivemotor 33 is connected by means of conductor wires 37 and 38 to an ACsource of power, movable normally closed contacts 55, 55a under thecontrol of relay 34 being interposed in wires 37 and 38, respectively.Contacts 55, 55a are closed when relay 34 is de-energized, and areopened when relay 34 is energized.

A thyristor 39 has its anode connected to relay 34 as shown, the cathodeof the thyristor being connected to the negative side of the DC powersource through wire 36. The thyristor has a control or gate electrode40; the thyristor is non-conductive, and thus the relay 34 isdeenergized, unless the control electrode 40 is at a predeterminedpotential which is positive with respect to the cathode. Under suchcondition, the thyristor becomes conductive, the coil of relay 34 isenergized, and contacts 55, 55a are opened to stop motor 33. The circuitshown in FIG. 2 includes circuit means, now to be described, whichrender control electrode 40 positive with respect to the cathode of thetransistor only after a sheet 13, having closed microswitch 28, fails toopen microswitch 32 within a predetermined time interval.

A unijunction transistor 42 has its first base 41 connected to negativeconductor 36 through a resistor 49. The second base 47 of transistor 42is connected to the positive wire 35 through a resistor 48. Thetransistor 42 becomes conductive between bases 41 and 47 when itsemitter 43 has a predetermined positive potential with respect to base41. Under such condition, the transistor 42 becomes conductive. Thecontrol electrode 40 of thyristor 39 is connected to base 41 oftransistor 42, as shown. Because of resistor 49, when transistor 42conducts, the control electrode 40 of thyristor 39 is at a higherpotential than the cathode of the thyristor, and thus the thyristorbecomes conductive. It will thus be seen that the thyristor, which isable to carry quite substantial currents, functions as a switch, beingunder the control of the transistor 42, which handles much smallercurrents. The transistor 42 is, in turn, controlled by a time delaycircuit, now to be described.

Connected across wire 36 and wire 35 downstream of switch 32 is atime-delay circuit having a variable resistor 46, a fixed resistor 45,and a condenser 44. When both switches 28 and 32 are closed, condenser44 begins to charge, the rate of charging being governed by the valuesof resistors 45, 46. Only after the positive terminal of condenser 44reaches a predetermined potential does the emitter 43 of transistor 42reach a sufficient positive potential for transistor 42 to becomeconductive between bases 41 and 47.-

A wire 57 is connected to wire 35 downstream of switch 28 but upstreamof switch 32. Wire 57 is connected to one terminal of the coil 52 of amagnetic clutch which is interposed in a drive train (not shown) betweenmotor 33 and the film transport mechanism (not shown) of the associatedmicrofilm flow camera. The other terminal of coil 52 is connected towire 36 through a wire 51. The switch 32 is of the double-pole type; thesecond pole, which is normally open but is closed when the poleconnected to wire 35 is open, is connected by a wire 53 to one terminalof the coil 54 of a counter relay, the other terminal of the coil 54being connected to wire 51.

The operation of the entire arrangement is as follows: During theinitial state of the apparatus, the main switch 55, 55a of the drivemotor 33 is closed and the motor is running. When no sheet 13 is in theapparatus, the switch 28 is open, whereas the switch 32 is closed. Assoon as a sheet 13 is inserted in the direction of the arrow A into thedriven sheet transport means 2 to 9 and reaches the scanning station 11,12 the feeler 26a is lifted, thereby closing the microswitch 28. Therelay 34, as a consequence of this, is energized, thereby to opencontacts 55, 55a, unless a circuit to coil 34 is cutoff by means of thethyristor 39. The thyristor is, however, made conductive only after apredetermined time delay, which is adjusted by varying the resistance46, by means of the RC member 45, 44 and the unijunction transistor 42,as soon as, due to the closing of the switch 28 and the charging of thecondenser 44, the control electrode 43 receives a positive potential ofa sufficient magnitude. The premature decay of this potential via theresistance 49 is prevented due to the positive potential which isimposed on the second base 47.

If a sheet 13 passes the scanning station 11, 12 in a normal, orderlyway, thereby opening the feeler 30a of the microswitch 32 before thecompletion of the charg-' ing of the condenser 44, the energizingcircuit for the relay 34 is interrupted before the thyristor 39 becomesconductive. The condenser 44 then discharges via the base 41 and theresistance 49, so that the circuit resumes its initial state, ready forthe next cycle.

' As indicated above, relay 34 may also operate an audible and/orvisible signal to give notice to the operator of abnormal operation ofthe sheet transport mechanism. Such audible and/or visible signal may beemployed in place of or in addition to the movable contacts 55, 55awhich stop the motor 33. Also, when the solenoid of the relay 34 has anappreciable distance of travel between the position in which contacts55, 55a are closed to that in which they are open, the repositioning ofthe solenoid plunger and contacts gives a visual signal of abnormaloperation of the transport mechanism when relay 34 is de-energized.

A camera incorporating the scanning apparatus of FIGS. 1 and 2 isfragmentarily shown in perspective in FIG. 3. The motor 33 drives theroller 19 through the medium of a belt 60 entrained over pulleys, asshown. The roller 6 is driven from the roller 19 by the means of a belt61 and pulleys on the roller shafts. A belt extends from a pulley on theshaft of roller 6 to an electromagnetic clutch 64 which includes theabove-disclosed clutch coil winding 52. A driving mechanism 65, whichincludes the electromagnetic clutch 64, drives a shaft 66 which isdriven by means of a pinion and a larger gear in mesh therewith, thedriving mechanism being driven when the coil 52 of the clutch 64 isenergized. Roll film 69, which is entrained over a sprocket or roller67, is advanced at the requisite speed to be exposed to copy a sheet ororiginal 13 progressing through the scanner.

The sheet 13 is illuminated, as above-described, by a bank of lamps 14which illuminate the forward face of the sheet. A similar bank of lamps,of which one is shown at 15 in FIG. 1, is disposed to illuminate therear surface of the sheet, there being means including the elongatedmirror 16 for photographing such rear surface of the sheet. The meansfor photographing the rear surface is similar to that, now to bedescribed, for photographing the forward face of the sheet.

Light reflected from the forward surface of the sheet 13 impinges uponthe elongated angularly disposed mirror 17 and is reflected therefrom toa canted elongated upper mirror 17 at one side of the apparatus. Themirror 71 is tipped, as shown, so as to reflect the thus received lightdownwardly upon a lower elongated tipped mirror 72. Light is reflectedfrom mirror 72 across the apparatus, as indicated, and is received upona canted mirror 74 which forwards it to an objective lens 70 of thecamera, the lens 70 having its focus in the plane of the film 69.

Although the invention is illustrated and described with reference toone preferred embodiment thereof, it is to be understood that it is inno way limited to the disclosure of such a preferred embodiment but iscapable 1. Apparatus for scanning a plurality of sheets which are fed insuccession through the apparatus, comprising driven transport means formoving s eets to be scanne through a scanning station, a first sheetdetector positioned upstream of the scanning station, a second sheetdetector positioned downstream of the scanning station, said transportmeans normally moving the leading end of a sheet from the first to thesecond detector in a predetermined first time interval, and signal meansoperative when a given second time interval at least slightly greaterthan the first time interval elapses between passage of the leading endof a sheet from the first to the second sheet detector, and a controlcircuit, means for energizing the control circuit, wherein the first andsecond sheet detector include series connected first and secondswitches, respectively, the signal means includes a relay having a coilselectively energized by the control circuit, a third, normally openswitch in the control circuit, and time delay circuit means for closingthe third switch to energize the relay coil at the end of said secondtime interval, said second time interval starting at the first instantthat both the first and second switches are closed during the handlingof said sheet by the sheet transport means.

2. Apparatus according to claim 1, wherein the first switch is normallyopen and is closed by the passage of a sheet past the first sheetdetector, and the second switch is normally closed and is opened by thepassage of a sheet past the second sheet detector.

3. Apparatus according to claim 2, comprising a DC source for thecontrol circuit and wherein the third switch has a control electrodewhich selectively renders the third switch conductive, and the timedelay circuit means includes an RC circuit having a series connectedresistance and condenser connected in parallel with the relay coil andto the control electrode of the third switch.

4. Apparatus according to claim 3, wherein the third switch is athyristor, and comprising a unijunction transistor having its first baseelectrode connected to the negative side of the control circuit and itssecond base electrode connected to the positive side of the controlcircuit, the emitter of the unijunction transistor being connected tothe positive side of the condenser in the RC circuit.

5. Apparatus according to claim 1, comprising means to count the numberof sheets passing through the scanning station, and means actuated bythe second sheet detector for operating the sheet counter.

6. Apparatus according to claim 1, comprising means which measures theelapsed time following passage of the leading end of a sheet by thefirst sheet detector, and wherein the signal means is rendered operativeby the elapsed time measuring means when a given second time interval atleast slightly greater than the first time interval elapses betweenpassage of the leading end of a sheet from the first to the second sheetdetector.

1. Apparatus for scanning a plurality of sheets which are fed insuccession through the apparatus, comprising driven transport means formoving sheets to be scanned through a scanning station, a first sheetdetector positioned upstream of the scanning station, a second sheetdetector positioned downstream of the scanning station, said transportmeans normally moving the leading end of a sheet from the first to thesecond detector in a predetermined first time interval, and signal meansoperative when a given second time interval at least slightly greaterthan the first time interval elapses between passage of the leading endof a sheet from the first to the second sheet detector, and a controlcircuit, means for energizing the control circuit, wherein the first andsecond sheet detector include series connected first and secondswitches, respectively, the signal means includes a relay having a coilselectively energized by the control circuit, a third, normally openswitch in the control circuit, and time delay circuit means for closingthe third switch to energize the relay coil at the end of said secondtime interval, said second time interval starting at the first instantthat both the first and second switches are closed during the handlingof said sheet by the sheet transport means.
 2. Apparatus according toclaim 1, wherein the first switch is normally open and is closed by thepassage of a sheet past the first sheet detector, and the second switchis normally closed and is opened by the passage of a sheet past thesecond sheet detector.
 3. Apparatus according to claim 2, comprising aDC source for the control circuit and wherein the third switch has acontrol electrode which selectively rEnders the third switch conductive,and the time delay circuit means includes an RC circuit having a seriesconnected resistance and condenser connected in parallel with the relaycoil and to the control electrode of the third switch.
 4. Apparatusaccording to claim 3, wherein the third switch is a thyristor, andcomprising a unijunction transistor having its first base electrodeconnected to the negative side of the control circuit and its secondbase electrode connected to the positive side of the control circuit,the emitter of the unijunction transistor being connected to thepositive side of the condenser in the RC circuit.
 5. Apparatus accordingto claim 1, comprising means to count the number of sheets passingthrough the scanning station, and means actuated by the second sheetdetector for operating the sheet counter.
 6. Apparatus according toclaim 1, comprising means which measures the elapsed time followingpassage of the leading end of a sheet by the first sheet detector, andwherein the signal means is rendered operative by the elapsed timemeasuring means when a given second time interval at least slightlygreater than the first time interval elapses between passage of theleading end of a sheet from the first to the second sheet detector.